1. Field of the Invention
This invention relates to transfer switches and, more particularly, to rotatable electrical transfer switches for switching power from a primary to a secondary source.
2. Description of the Prior Art
Transfer switches are highly useful devices for switching power from a primary to a secondary source, such as from a utility to a mobile generator, during power outages. Conversely, transfer switches are employed to retransfer the load to the primary source when a primary source of power is available again, thereby disconnecting the secondary source.
For years, transfer switching systems have been used to facilitate emergency power for hospitals, subways, schools, airports, office buildings, and other commercial structures equipped with a secondary power source. Frequently, consumers also employ transfer switches to switch to an alternate power supply to avoid "peak time" utility charges. Some examples of power transfer switches are disclosed in U.S. Pat. Nos. 346,020; 549,810; 1,213,073; 3,072,828; 3,167,620; and 4,157,461.
Heretofore, many transfer switches have been unreliable for such reasons as overheating, complex construction, contact destruction due to arcing during normal operations, and susceptability to contact damage during short circuit condition. Thus, there has been a need for a transfer switch that obviates many of the unreliable circumstances.